We have observed the first Resonance Raman spectra of cytochrome P450 from pseudomonas putida using near ultraviolet laser excitation. We propose to extend our measurements using tunable near ultraviolet laser sources in conjunction with synchronous detection systems. The main objective is to use resonant Raman scattering to gain new information about the active site structure and function of cytochrome P450 and to achieve a better understanding of metalloporphyrin optical absorption spectra in the Soret region. Experiments involving intact cells, isotopic labels, and low temperatures are proposed in addition to measurements of the stable intermediate states of P450 catalysis. The theoretical implications of Soret band excitation profiles will also be studied.